Upstream oil field exploration and production operations, including drilling, completion, stimulation, water injection, and other fluid and gas injection processes, often require using chemical and solid materials to temporarily seal off regions of very high permeability rocks—also known as a “thief zones.” In drilling and completion, sealing off thief zones prevents lost circulation of drilling and completion fluids. In stimulation and other production and recovery enhancing processes, sealing off thief zones improves the uniformity of the injected stimulation fluid entering the formations along the trajectory of the wellbore, leading to improved hydrocarbon production and recovery. Efficient plugging of the thief zones can lead to more optimal short-term treatments as well as tending to increase the long-term profitability of the hydrocarbon extraction from subterranean formation. If not properly designed, the materials injected into the well could fail to seal the thief zones, or worse, they could damage the formation permeability such that the reservoir could become substantially less productive.
In order to create strong plugs, viscous fluids containing fibers and/or solid particles are often mixed by surface equipment prior to the injection. The fibers and/or particles are expected to interact together and form strong flocs and/or clusters. The flocculation and the coagulation are known to be highly sensitive to the viscosity of carrying fluid, the injection rate and the concentration of certain additives. The quality control of the resulting mixture is completed by visual inspection on the surface. However, when injected into the formation, the operator has no indication about interaction of the dispersed phase even though it is a very important condition for an efficient placement of the treatment fluid. Indeed, an early flocculation/coagulation will plug the downhole equipment and a late one will result in an unsuccessful fluid placement.